1. Field of the Invention
The present invention relates to an apparatus for measuring a shape of lens frames in eyeglasses by means of a measuring element.
2. Description of the Prior Art
Conventionally, there is developed an apparatus for measuring a shape of lens frames in eyeglasses by contacting a measuring element with grooves of the lens frames.
On the other hand, there may be lens frames which are easily deformable by an external force since a rim of the frames is narrow in width in a direction perpendicular to an optical axis of lenses of eyeglasses which are inserted into the frames.
There are also so-called crab-eye shaped lens frames (hereinafter referred to as elongate lens frames) of eyeglasses whose longitudinal distance is smaller than lateral distance, viewing from the front of the eyeglasses. Such lens frames have a rim whose width is narrow, to easily deform by operation of an external force, as mentioned above.
There is a problem that a nose pads or ear hooks of deformable lens frames, for example, the aforementioned elongate lens frames are subjected to deform and therefore a shape of the elongate frames can not be precisely measured, when the elongate lens frames are measured by the frame shape measuring apparatus, if the rotational speed or rotational direction of the aforementioned measuring element is substantially constant.